Physicochemical and Functional Modifications of Hemp Protein Concentrate by the Application of Ultrasonication and pH Shifting Treatments

Abstract

According to the Food and Agriculture Organization (FAO), protein demand is expected to increase globally by around 40% by 2030 as a response to the world’s population growth. Due to their clean label, vegan or vegetarian based applications, nutritional value, and cost-efficient properties, plant-based proteins have been widely studied. However, most of the alternatives currently found in the market have some challenges because of their poor solubility, emulsifying, gelling, and foaming attributes. Hemp seed protein has gained increasing attention due to its unique amino acids and fatty acids profiles. In this study, commercial HPC mixtures were adjusted to pH 2, 4, 6, 8, 10, and 12 followed by ultrasonication (US) for 5 min (5 s on: 5 s off) and incubated for an hour before neutralizing to pH 7. Following the treatments, the samples were analyzed for their hydrodynamic diameter, conductivity, zeta potential, polydispersity index, surface hydrophobicity, solubility, electrophoresis (SDS-PAGE), free sulfhydryl group, and optical characteristics. The samples treated with ultrasound at pH 8 and 10 significantly (p < 0.05) enhanced the solubility of the hemp seed protein by 12.12% and 19.05%, respectively. Similarly, the samples treated with ultrasonication and pH shifting at pH 6, 8, and 10 also significantly increased the amount of free sulfhydryl content (p < 0.05) to 41.6, 58.72, and 46.54 mmol/g from 32.8 mmol/g, respectively. This study shows that the application of ultrasonication and pH shifting is a promising alternative method to modify the functional properties of HPC and widen their applications in the food, cosmetics, and pharmaceutical industries.

Physicochemical, Structural, and Functional Properties of Hemp Protein vs Several Commercially Available Plant and Animal Proteins: A Comparative Study

“…Regarding −SH content, hemp protein had a −SH content of 34.85 μmol/g, which is significantly higher than those of its two plant-based peers (19.83 μmol/g for soy and 13.07 μmol/g for pea) but is lower than those of the two animal-based counterparts (37.41 μmol/g for whey and 48.54 μmol/g for egg albumin) (Table ). These results are in the range of −SH contents presented in previous studies: 32.82 μmol/g for hemp, 50.53 μmol/g for egg white, 39.84 μmol/g for whey, 18.05 μmol/g for soy, and 12.60 μmol/g for pea, respectively. ,− Some variations could be attributed to the protein sources. The higher −SH content in hemp protein is related to higher amounts of cysteine, which has an active −SH group, compared to soy or pea.…”

High‐intensity ultrasound treatment: An effective way of modifying thermal and rheological properties of sunnhemp (Crotalaria juncea) protein isolate (SHPI) by varying ultrasound amplitude and time

“…As a result of this phenomena, cavitational forces are developed, which are responsible for smaller particle size of the medium and creating high shear forces (Zhao et al, 2022). Numerous authors have shown that ultrasound technology can modify the functional, structural, thermal, and rheological behavior of protein foods by altering their secondary characteristics (Hertzler et al, 2020; Kahraman et al, 2022; Kaur et al, 2021; Lafarga et al, 2018; Lo et al, 2022; Sidhu et al, 2019; Thalía Flores‐Jiménez et al, 2022; Wang et al, 2017). However, no information is available on the extraction and modification in the physico‐chemical, thermal, and rheological properties of sunnhemp proteins.…”

Structural Characterization, Technofunctional and Rheological Properties of Sesame Proteins Treated by High-Intensity Ultrasound

“…In other study conducted by Amiri et al [59] and Zhang, Regenstein, Zhou, and Yang [38], the total −SH group was found to decrease after ultrasound treatment, probably due to the formation of disulfide bonds, and a reverse trend was observed for free −SH groups that could be related to the disruption of protein structure and reduction in particle size. Kahraman et al [60] stated that the reduction in free −SH groups could be associated with the oxidation of disulfide bonds with hydrogen peroxide, which forms by the generation of free radicals during sonication.…”